U.S. Pat. No. 4,717,205 discloses a cutter in the form of a machine of the above defined type comprising a tool carrier consisting of a hollow arm and a driving member consisting of a sprocket accommodated inside of the hollow arm, in the front end thereof. On each side of the sprocket there is a bearing, each arranged in a bearing hole in a broad side of the hollow arm. Outside of each bearing there is a rotational tool. Because of this conventional bearing arrangement there is a considerable distance between the two rotational tools. This increases the distance between the two cuts which is a distinct disadvantage. Another shortage is that the machine is void of any kind of tool guard and nor is any solution of that safety issue suggested in the disclosure of the said US patent.
EP-1,252,956-A1 also discloses a machine of the type defined in the preamble. In this machine, the tool carrier consists of a solid bar of sufficient width for the provision of a desired bending resistance to the tool carrier and also for allowing the provision of a single bearing of desired width in the front end of the bar. The latter is an important technical achievement, making it possible to reduce the distance between the two rotational tools, i.e. the two cuts. On the other hand, the design disclosed in EP-1,252,956-A1 requires machining of the front section of the bar, which involves considerable costs, which is a drawback. Besides, a thick, solid bar is rather heavy which also is a drawback when the machine is a portable working machine. Nor does the bar provide any efficient protection of the power transmission and does not promote a good solution of problems concerning the blade guard issue. In particular there is a fixedly mounted double-walled side guard, but this guard does not protect the sides of the belt transmission. Therefore concrete parts or even loose wall cables could reach the inside of the belt and the belt pulleys. This is detrimental to the reliability of the machine and could possibly even be a safety hazard.